Metallurgical furnace.



3 SHEETS-SHEET 1.

PATENTED FEB. 7, 1905.

m a Y 65 ZYQWWW R L LLOYD & P THILL METALLURGICAL FURNACE.

APPLIOATION FILED MAR 25 1903 No. 781,834. PATENTED FEB. 7, 1905. R. L. LLOYD & P. THILL.

METALLURGICAL FURNACE.

APPLICATION FILED MAR. 25. 1903.

SBHEBTS-SHBET 2.

W p. muontozd,

No. 781,834. PATENTBD FEB. 7, 1905.

R. L. LLOYD & P. THILL.

METALLURGICAL FURNACE.

APPLICATION IILED MAR. 25, 1903.; "g msauna-slum a. .1 A??? :Illl

row

Patented February '7, 1905.

RICHARD L. LLOYD AND PETER THILL, OF GREATFALLS, MONTANA.

METALLURGICAL FURNACE.

SPECIFICATION forming part of Letters Patent N0. 781,834, dated February 7, 1905.

Application filed March 25,1903. Serial No. 149,499.

To (all whom it 71111.7 concern:

Be it known that we, RICHARD L. LLOYD and Pn'rnn THILL, citizens of the United States, and residents of (jrreatfalls, in the county of Cascade and State of Montana, have invented certain new and useful Improvements in Metallurgical Furnaces, of which the following is a specification.

()ur invention relates to that class of furnaces adapted for the manufacture of sulfuric acid from pyritic ores; and it is particularly adapted to those furnaces which work without other fuel than the heat generated by the oxidation of the ore. A furnace of this general type (though, of course, not embracing ourimprovements) is the well-known Mc- Dougall, such as is described in Lunges Sulfur/c Ale/(l and ill/MU, second edition, page 260. The invention is not confined to furnaces thus employed.

in ore-roasting furnaces of the general type named a numberof objections have been made with which we aim by our invention to overcome. All of these furnaces with which we are familiar have a number of successive hearths, from one to the other of which the material is dropped in the process of roasting. The great objection to this is that it makes an excessive quantity of flue-dust, which not only impairs the success of the operation, but is difficult to handle. The greater part of the dust is made by dropping the material from one hearth to another. To overcome this objection, we provide a helical continuous hearth, making as many turns as may be desired to give the surface required for the proper roasting of the material passing through the furnace. To effect the continuous progression of the finely-divided ore, we arrange in each of the spaces between the turns of the helix stirrer-arms, which may be of ordinary or well-known construction, there being no essential novelty in these, many forms being in use in various furnaces. They may be cooled in any desired manner by means i well known to engineers. It is manifest that the operation of arms (in the helical spaces indicated) by continuous or rotary motion is impossible. \Ve therefore provide for a rotary reciprocation of the arms and arrange for their following the pitch of the helix in their downward movement (where the arms are, as illustrated in the present case, angularly displaced ninety degrees apart) for a little more than half a revolution. At the end of their stroke they are first raised 'ortically a sufficient distance to clear the body of ore on the hearth and are then rotated baclnvard, being-depressed at the beginning of the stroke until they again engage the ore on the hearth. As thus constructed it is manifest that since the central shaft and stirrer-arms of a commercial furnace weigh several tons a considerable amount of power is required to operate the furnace.

A further feature of our invention, therefore, consists in means for diminishing this excessive power by the expedient of counterbalancing the feeding devices. so that as one of the fumace-operating mechanisms is lowered the counterweight is raised. This may conveniently be done by a system of levers in furnaces of moderate or small capacity; but we find it more convenient, as well as more eliicient, to support the mechanism upon hydraulic cylinders and connect the latter by pipes of sufficient capacity. Thus as one sinks the other rises, and the amount of power required to operate the furnace will be, so far as the lifting is concerned, greatly reduced.

The accompanying drawings show a furnace constructed according to our invention.

In the drawings, Figure 1 is a vertical section throu h such a furnace as we have described. F ig. 2 is a detailed diagram showing the outline of the hearth separate from the furnace. Figs. 3 and a are details of the driving mechanism. Fig. 5 is a plan view, with the top removed, of the parts shown in Fig. 1. Fig. (5 is a diagrammatic view of the counter-balancing mechanism.

In Fig. 1, A is the wall of the furnace, and B is the continuous helical shelf or hearth to which I have referred. formation is indicated in diagram in Fig. 2. O C are the feeder-arms, often called stirrers. These arms are provided with rabbles In practice we find it desirable to turn Its particular con- 7 these rabbles in opposite directions on successive arms, so that one set, for example, tends to move the ore radially outward as well as forward on the hearth and the next set on the succeeding arm tends to move it inward toward the center. This exposes all of the ore to the action of the draft and assists in its thorough oxidation. A is the cover of the furnace. E is the hopper from which the pyritic ore is supplied. F is the receivingchute at the end of the furnace, from which the car G is filled in the usual way. At the lower part of the figure is shown the means for imparting rotary reciprocation to the feeder-arms. The pulleys H H are operated in the usual way by crossed belts, (not shown,) one driving the gears I I in one direction and the other in the opposite. The driving-pinion K is of such length that the main driving-gear L may be moved up and down without losing mesh. This gear is fast with the threaded drum M, which rotates in a nut N. O is a hydraulic cylinder to which water is supplied by the pipe P.

Figs. 3 and 4 show the detail of the arrangement by which the feeder-arms are actuated so as not to disturb the ore on the backward stroke. These figures are to be read in connection with Fig. 1. M is a projection from the drum M, which acts as a step for the shaft D. A ball-bearing Q is prdvided, so that the shaft will remain stationary while the drum M revolves. Lugs D are formed upon the shaft D, and between these lugs projections M M from the step M may play. It is manifest that the shaft D will remain stationary only until the lugs M engage with the projections D, when they begin to rotate the shaft. By this arrangement when the feederarms are at the end of their stroke and the belt is shifted from one to the other of the pulleys H H the drum M reverses its rotation and begins to rise upon the thread, carrying the shaft vertically with it. The shaft does not rotate, inasmuch as the lugs M are moving away from the lugs D toward the other set. When the two sets of lugs are in engagement, however, the shaft, which has been raised sufliciently for the stirrer-arms to clear the ore, rotates backward to the end of its stroke, and thereupon the belt is again shifted by any usual contrivance well known in the art. The lugs M rotate in opposite direction away from the lugs D, the shaft and its arms are lowered into the ore, and another stroke is taken. The feeding mechanism thus outlined is new with us, and we desire to claim it, whether used with a furnace of our particular construction or otherwise. It is, we believe, new to reciprocate the feeding arrangement by amotion which resembles the four-motion feed, for example, of a sewing-machine, and it is manifest that this has great advantages in procuring a steady and continuous feed of the ore through the furnace without breaking up and interrupting the motion during the backward stroke of the feeding appliances.

Fig. 6 shows how we may balance the feeding apparatus of the furnaces one against another. In this figure, O O are the hydraulic cylinders of the several furnaces, the rest of the apparatus not being illustrated, as it is unnecessary for our purpose. 'P P are the pipes from the various hydraulic cylinders, connecting with a common header P. This communicates with a cylinder the contents of which may be equal to that of the cylinders O or somewhat greater. The piston S reciprocatcs in this cylinder, carrying the table T, on which weight I/V may be disposed suflicient to balance the various furnaces. By this means each of the furnaces has independent motion, and the weight of the moving parts is efficaciously counterbalanced.

The revolution of the central shaft, it will be seen, amounts to a little more than twice the angular displacement of the stirrer-arms in order to insure the feed positively carrying the ore over the entire space between any two arms. W e have preferred to place the arms on the shaft at ninety degrees apart; but if other displacements are used the revolution of I the shaft should be correspondingly changed.

For example. if the arms are radially displaced one hundred and eighty degrees the shaft would make a little more than a complete revolution.

Having thus described our invention, what we claim, and desire to protect by Letters Patent of the United States, is-

1. In a metallurgical furnace, a stationary longitudinally-curved hearth for the ore, in combination with an ore-feeding mechanism disposed in the space between the turns of the hearth.

2. In a metallurgical furnace, a stationary helical hearth for the ore, combined with an ore-feeding mechanism disposed in the space between the turns of the helix.

3. In a metallurgical furnace, the combination of a hearth forming a continuous longitudinally-curved path for the ore, extending from the mouth to the discharge of the furnace, and disposed about a vertical axis, reciprocating feeding mechanism, means for causing it to follow the curve of the hearth in feeding the ore, and means for withdrawing it from contact with the ore during its backward stroke.

4. In a metallurgical furnace, the combination with a helical hearth, of feeder-arms, and means for imparting to them a rotary'reciprocation following the pitch of the helix.

5. In a metallurgical furnace, the combination with a helical hearth, of feeder-arms, means for imparting to them a rotary reciprocation following the pitch of the helix,

means for raising them above the ore at the end of their stroke, and means for lowering them into engagement with the ore.

6. in a metallurgical furnace, the combination with a helical hearth having asubstantially vertical axis of feeder-arms and means for imparting to them a rotary reciprocation in contact with the ore during their forward or downward stroke, and out of contact therewith during their backward or upward stroke.

T. in a metallurgical furnace, the combination with a helical hearth, of a shaft carrying feeder-arms, means for imparting rotary reciprocation to the shaft and arms, a guide for causing the motion to follow the pitch of the helix, and means for raising the shaft at the end of its stroke so that the backward movement of the arms is out of effective contact with the ore.

b. The combination with a plurality of furnaces provided with feeding mechanisms having a central shaft and stirrer-arms with some vertical movement, of means for counterbalancing the weight of thefeeding mechanisms.

9. The combination, with the feeding mechism of a furnace having a central shaft and stirrer-arms with some vertical movement, of means for counterbalancing its weight.

10. The combination, with a furnace-feeding mechanism consisting of a central shaft with stirrer-arms, having a limited vertical movement, of a hydraulic cylinder and piston supporting the feeding mechanism, and means for counterbalancing the thrust on the piston.

ll. in a metallurgical furnace, a feeding mechanism comprising a central shaft with radial stirrer-arms and means for imparting to the shaft a rotary reciprocation over approximately twice the angular displacement of the arms.

12. Ina metallurgicalfurnace, the combination of a helical hearth with a feeding mechanism comprising a central shaft having radial arms and means for imparting to the shaft a rotary reciprocation over approximately twice the angular displacement of the arms.

13. In a metallurgical furnace, a feeding mechanism consisting of a central shaft with radially-dispose d stirrerarms, means for imparting to the shaft a rotary reciprocation over approximately twice the angular displacement of the arms, and means for removing the latter from effective contact with the ore during their backward movement.

14. In a metallurgical furnace, the com bination of a helical hearth with a feeding mechanism comprising a central shaft having radial arms, means for imparting to the shaft a rotary reciprocation of approximately twice the angular displacement of the arms and means for removing the feed from effective contact with the ore during the backward stroke.

15. The combination, with a number of furnace feeding mechanisms having vertical movement, of a common counterbalance for all the mechanisms.

16. The combination with a number of furnztce feetliiig' mechanisms supported each by a hydraulic cylinder and piston, of a main hydraulic cylinder, pipes connecting all of the cylinders, and a weighted piston in the main cylinder.

In witness whereof we have hereunto set our hands, this 16th day of March, 1903,in the presence of two witnesses.

RICHARD L. LLOYD. PETER THlLL.

\Vitnesses:

CHAS. S. MoCoNNnLL, B. ASEMANN. 

